Process of refining used oil



Patented Mar. 11, 1930 if STATES JOSEPH C. PATRICK, OF KANSAS CITY, MISSOURI PROCESS OF REFINING USED OIL No Drawing.

This invention relates to the refining of used mineral lubricating oils and has for its object to produce a simple and economical process by which used mineral oils which have been subjected to dilution by unsaturated hydrocarbons or water, but more particularly those drained from the crank case of an automobile, may be refined and the oil returned to as good, or "better, lubricating value than when new.

It is well known that oil as drawn from the crank case of an engine has not been worn out, but is merely unfit for use as a lubricant because of tarry asphaltic com ounds, unsaturated hydrocarbons, dust, irt, diluents,

free water, free carbon, and metals both in colloidal and free form as worn or chipped from the bearings of the engine. 1 The purpose of the invention, therefore, is

to produce a process by which all of the above impurities will be removed from the oil, the oil being completely refined and returned to substantially its original color and nonmalodorous condition, the lubricating value of the oil being in fact better than that of the original oil.

In carrying out the invention, I first separate from the oil all free water, that would otherwise dilute the concentrated acid later 0 used in the process, preferably by permitting ghe oil to stand quiescent for from one to two ays.

The oil is then drawn ofi to an acid treating tank and heated to a temperature of approximately 120 F., then 2% by volume of 66? B. commercial sulphuric acid is added;

the mixture of oil and acid is then agitated from fifteen minutes to a'half hour, the temperature of approximately 120 F. being 40 maintained. The elevated temperature increases the fluidity of the oil, insures a more intimate contact with the acid and accelerates the reaction. The acid-coagulates the free carbon, removes tarry coloring bodies, partially removes the unsaturated hydrocarbons. and partially dehydrates the oil, forming all of the above c'ontaminations into a heavy sludge that settles within a few hours to the bottom of the tank.

The supernatant oil is now drawn ofi iron.

Application filed October 28, 1927. Serial No. 229,534.

the acid treating tank to a suitable still where it is heated under a high degree of vacuum to approximately 450 F. This temperature, under a high vacuum, is sufficient to vaporize the diluents (unsaturated hydrocarbons and 5 entrapped Water) in the oil, but is not sufficiently high to distill the lubricating oil or break down or crack the desired lubricating components of the oil.

After the oil has been subjected to distillation, it is withdrawn while hot and immediately treated with from 15% to 18% by weight of fullers' earth in such a manner as to insure intimate contact. It is to be understood that the fullers earth reacts violently with oil and that the two must be mixed with care by periodic addition of a small quantity I of one to the other. The fullers earth reacts with the colloidal metals, effects neutralization by adsorption, and coagulates all such materials and suspended impurities, and such material being of greater specific gravity thlafi the oil, will settle to the bottom of the It is also advisable to add to the fullers earth an anhydrous oxide, such as lithium oxide, in suflicient quantity to absolutely insure that all traces of acid in the oil shall be neutralized. It has been found however, if a suflicient quantity of fullers earth has been added, that it will efiiciently neutralize the acid without the addition of an anhydrous oxide, whose carbonate is not soluble in water.

The coagulated mixture above described settles to the bottom of the tank as a heavy sludge and after substantiall fortyeight hours the supernatant oil may be withdrawn from the sludge. The oil thus treated will be found to have returned to substantially its original or improved condition, and to possessa better color and lubricating value than the original oil.

From the above description it will be apparent that I have produced a process of re- 1 fining used oils which possesses all of the features of advantage set forth as desirable, and while I have described and claimed the preferred embodiment of the invention, it is to be understood that I reserve the right to make all such changes as properly fall within the spirit and scope of the appended claims.

I claim:

1. The method of refining used mineral lubricating oil containing water and hydrocarbon diluents which consists in removing free water from the oil, heating the oil to approximately 120 F., adding sulphuric acid to the oil while hot, agitating the mixture, removing the oil from the resultant sludge, vaporizing diluents from the oil, and then adding suificient active adsorptive reagent to clari decolorize and neutralize the oil, and finally drawing off the purified oil.

\ 2. The method of refining used mineral lubricating oil containing water and hydrocarbon diluents which consists in removing free water from the oil, heating the oil, adding concentrated sulphuric acid to the oil while hot, removing the oil from the resultant sludge, heating the oil to a temperature above 450 F. but below cracking temperature, then adding an active adsorgtive reagent and finally drawing off the puri ed oil.

3. The method of refining used mineral lubricating oil containing water and hydrocarbon diluents, which consists in removing free water from the oil, heating the oil to approximately 120 F., adding sulphuric acid to the oil while hot, removing the oil from the resultant sludge, heatin the oil thereby vaporizing the diluents, a ding to the Oil while hot an active adsorptive reagent to clarify, decolorize, and neutralize the oil and I finally drawing off the purified oil.

4. The method of refining used mineral lubricating oil containing water and hydrocarbon diluents which consists in removing .free water from the oil, heating the oil to approximately 120 F., adding 2% by volume of 66 B., commercial sulphuric acid, agitating the mixture while maintaining it at said temperature, removing the oil from the resultant sludge, vaporizing diluents from the oil, adding to the oil while hot 15 to 18% by weight of fullers earth and finally drawing off the purified oil.

5. The method of refining used mineral lubricating oil containing water and hydrocarbon diluents which consists in removing free water from the oil heatin the oil to approximately 120 F., adding su phuric acid to the oil while hot, agitating the mixture, removing the oil from the resultant sludge, vaporizin diluents from the oil, and then adding s cient active adsor tive reagent to clarify, dec'olorize and neutrafize the oil, adding an anh drous oxide to neutralize the oil, and final drawing 01f the purified oil.

6. The method of refining used mineral lubricating oil containing water and hydrocarbon diluents which consists in heating the oil to approximately 120 F., adding sulphuric acld to the oil while hot, agitating the mixture, removing the oil from the resultant sludge, vaporizing diluents from the oil, and then adding suflicient active adsorptive reagent to clarify, decolorize and neutralize the oil, and finally separating the reagent and adsorbed impurities from the purified oil.

7. The method of refining used mineral lubricating oil containing water and hydrocarbon diluents, which consists in heating the oil to approximately 120 F., adding sulphuric acid to the oil while hot, removing the oil from the resultant sludge, heating the oil thereby vaporizing the diluents, adding to the oil while hot an active adsorptive reagent to clarify, decolorize, and neutralize the oil, and finally separating the reagent and adsorbed impurities from the purified -oil. In testimony whereof I afiix my signature.

JOSEPH C. PATRICK. 

